Vol. 2, No. 3 Contents
Headline Back Issues
Summer 1998
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Fisherman helping scientists track leatherback sea turtles By Suzy Fried
In Nova Scotia's coastal communities, the leatherback sea turtle is becoming a celebrity of sorts, as scientists and fishermen collaborate to gather information that will help in developing conservation measures for the engaging, and endangered, creature. On average, leatherbacks measure about eight feet/two and a half meters long from head to tail, weigh nearly half a ton/450 kilograms, and can stretch their flippers to spans of six feet/two meters. But neither their hardy physique nor international endangered status has prevented drastic declines in their populations, according to Mike James of Acadia University in Wolfville, Nova Scotia, coordinator of the North Atlantic Leatherback Turtle Working Group. The group formed in 1995 under Chris Harvey-Clark, head veterinarian at Dalhousie University in Halifax, who developed a plan to guide leatherback conservation efforts in Nova Scotia and the other maritime provinces. But when other job responsibilities prevented Harvey-Clark from pursuing the project further, the group languished for a couple of years until James, who is researching leatherback turtles for a master's degree, revived it. Since then, the working group has recruited more than 100 fishermen in the province to call in turtle sightings, and to photograph the animals when possible. The working group hopes that turtle conservation efforts will benefit from better understanding of the turtles' travels and the risks they face. Funding from World Wildlife Fund Canada and the Canadian Wildlife Federation have supported the group's efforts along with $2,000 raised by third-graders at an Ontario school. Mysterious travelers "We do not really understand what exactly is accounting for such a huge decline" in leatherback turtle populations, said James. He explained that once the hatchlings are out of the nest, they are hard to track - especially males, who don't come ashore to nest as females do. Scientists estimate leatherback turtle populations by counting females found on known nesting beaches, he said. In 1982, scientists counted 115,000 nesting female leatherbacks. By 1995, that number had dropped to 34,500, with beaches that may have been visited by up to 300 females in the past being used for nesting by only a dozen, James said. James has given water-resistant single-use cameras, donated by Fuji Canada, to fishermen working off of Nova Scotia's east and south shores, where leatherbacks arrive in June, and are spotted most in August and September. Photos are valuable in tracking individual animals, which can be identified by distinctive markings on their heads. The working group was also making plans during the summer to track turtles using passive integrated transponder (PIT) tags that are implanted into the shoulder muscles of turtles caught in fishing gear or stranded in Nova Scotia waters before they are released back into the sea. "It sounds invasive, but for an animal that can be 450 kilograms or larger, it is a vary small impact," according to James, who describes the turtles as "dinosaur-esque."
Poachers one of several threats Another factor is loss of nesting habitat due to both development and natural causes such as beach erosion. Vessel strikes may also injure or kill some turtles. But even more of a problem is the proliferation of trash in the ocean - especially plastic bags, which resemble the jellyfish on which the turtles feed. The inside of a leatherback's esophagus is lined with razor-sharp pointed spines that help it swallow jellyfish, but that also prevent the turtle from spitting up garbage it has swallowed by mistake. "Leatherbacks that have been necropsied on beaches have shown lots of plastics, tar, Styrofoam, garbage. It eventually plugs their digestive tract and they starve to death," said James. And, like other marine animals, leatherback turtles can get entangled in fishing gear. Typically, their front flippers get caught and they can often be freed, but if the whole turtle is caught in a net, it may drown. "You can't penalize accidental bycatch, and you don't want to," James asserted. "We want to maintain good relationships with fishermen. It is the fishermen who report valuable information the working group needs," he said, adding that he believes most Nova Scotia fishermen release turtles from their gear alive. "The majority of fishermen in this province really do seem to like turtles. I don't think we're getting that high a rate of fishery related-mortality here," James said. Terry Baker, a fourth-generation fisherman who fishes for swordfish and lobster east of Halifax down to Sable Island, has spotted leatherbacks in the water since he started going out on fishing boats with his parents as a young boy. He became involved in the turtle-watching project through the Fishermen and Scientist Research Society, after James came to the group's annual meeting two winters ago. "We don't mind keeping an eye out for them," said Baker. "We're there anyway. We don't see them often but we see some." Expanding the fan club The working group intends to broaden its effort with a curriculum unit on leatherback turtles it is developing for use in Maritime schools, said James. High school science and oceanography teacher Albert D'Entremont of West Pubnico, a community south of Yarmouth, Nova Scotia, is a working group volunteer who joined after encountering several leatherbacks two summers ago while sailing off the coast of Nova Scotia with his wife, Myrna. He plans to incorporate leatherback turtles into his lesson plans this school year. Meanwhile, leatherbacks continue to charm Nova Scotia's coastal communities. As he prepared to leave for another sailing trip this past July, D'Entremont said he hoped he would spot the turtles again, perhaps this time with tags or known identifying markings. "These are gorgeous animals. Like the kids would say, `they're awesome.' They're totally captivating." For more information on the Leatherback Turtle Working Group's efforts, call Mike James at 1-888-729-4667 from Atlantic Canada or (902) 585-1705 from the US. |
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Wolfville, Nova Scotia - Their images grace posters in storefront windows. They spend hours basking in the sun and dining on exotic snacks. Delighted fans snap their photos at every opportunity.
Scientists have been tagging nesting female turtles with signal-emitting devices using various methods, with different degrees of success. The PIT tag does not emit a signal, but can be scanned the way product codes on groceries are scanned at the checkout, allowing scientists to track the turtle's travels, provided they can get close enough to the animal to scan its tag.